From: Qu Wenruo Date: Fri, 20 Feb 2026 03:41:51 +0000 (+1030) Subject: btrfs: reduce the size of compressed_bio X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=b05342fe47b9828d004baf2b24cccd0479de54a5;p=thirdparty%2Fkernel%2Flinux.git btrfs: reduce the size of compressed_bio The member compressed_bio::compressed_len can be replaced by the bio size, as we always submit the full compressed data without any partial read/write. Furthermore we already have enough ASSERT()s making sure the bio size matches the ordered extent or the extent map. This saves 8 bytes from compressed_bio: Before: struct compressed_bio { u64 start; /* 0 8 */ unsigned int len; /* 8 4 */ unsigned int compressed_len; /* 12 4 */ u8 compress_type; /* 16 1 */ bool writeback; /* 17 1 */ /* XXX 6 bytes hole, try to pack */ struct btrfs_bio * orig_bbio; /* 24 8 */ struct btrfs_bio bbio __attribute__((__aligned__(8))); /* 32 304 */ /* XXX last struct has 1 bit hole */ /* size: 336, cachelines: 6, members: 7 */ /* sum members: 330, holes: 1, sum holes: 6 */ /* member types with bit holes: 1, total: 1 */ /* forced alignments: 1 */ /* last cacheline: 16 bytes */ } __attribute__((__aligned__(8))); After: struct compressed_bio { u64 start; /* 0 8 */ unsigned int len; /* 8 4 */ u8 compress_type; /* 12 1 */ bool writeback; /* 13 1 */ /* XXX 2 bytes hole, try to pack */ struct btrfs_bio * orig_bbio; /* 16 8 */ struct btrfs_bio bbio __attribute__((__aligned__(8))); /* 24 304 */ /* XXX last struct has 1 bit hole */ /* size: 328, cachelines: 6, members: 6 */ /* sum members: 326, holes: 1, sum holes: 2 */ /* member types with bit holes: 1, total: 1 */ /* forced alignments: 1 */ /* last cacheline: 8 bytes */ } __attribute__((__aligned__(8))); Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 3a5701f68172e..e897342bece1f 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -330,7 +330,6 @@ void btrfs_submit_compressed_write(struct btrfs_ordered_extent *ordered, cb->start = ordered->file_offset; cb->len = ordered->num_bytes; ASSERT(cb->bbio.bio.bi_iter.bi_size == ordered->disk_num_bytes); - cb->compressed_len = ordered->disk_num_bytes; cb->bbio.bio.bi_iter.bi_sector = ordered->disk_bytenr >> SECTOR_SHIFT; cb->bbio.ordered = ordered; @@ -560,7 +559,6 @@ void btrfs_submit_compressed_read(struct btrfs_bio *bbio) em_start = em->start; cb->len = bbio->bio.bi_iter.bi_size; - cb->compressed_len = compressed_len; cb->compress_type = btrfs_extent_map_compression(em); cb->orig_bbio = bbio; cb->bbio.csum_search_commit_root = bbio->csum_search_commit_root; diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h index 65b8bc4bbe0bf..84600b284e1e2 100644 --- a/fs/btrfs/compression.h +++ b/fs/btrfs/compression.h @@ -48,9 +48,6 @@ struct compressed_bio { /* Number of bytes in the inode we're working on */ unsigned int len; - /* Number of bytes on disk */ - unsigned int compressed_len; - /* The compression algorithm for this bio */ u8 compress_type; diff --git a/fs/btrfs/lzo.c b/fs/btrfs/lzo.c index 79642e02181b9..0c90937707395 100644 --- a/fs/btrfs/lzo.c +++ b/fs/btrfs/lzo.c @@ -431,6 +431,7 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) struct workspace *workspace = list_entry(ws, struct workspace, list); struct btrfs_fs_info *fs_info = cb->bbio.inode->root->fs_info; const u32 sectorsize = fs_info->sectorsize; + const u32 compressed_len = bio_get_size(&cb->bbio.bio); struct folio_iter fi; char *kaddr; int ret; @@ -460,14 +461,14 @@ int lzo_decompress_bio(struct list_head *ws, struct compressed_bio *cb) * and all sectors should be used. * If this happens, it means the compressed extent is corrupted. */ - if (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, cb->compressed_len) || - round_up(len_in, sectorsize) < cb->compressed_len)) { + if (unlikely(len_in > min_t(size_t, BTRFS_MAX_COMPRESSED, compressed_len) || + round_up(len_in, sectorsize) < compressed_len)) { struct btrfs_inode *inode = cb->bbio.inode; btrfs_err(fs_info, "lzo header invalid, root %llu inode %llu offset %llu lzo len %u compressed len %u", btrfs_root_id(inode->root), btrfs_ino(inode), - cb->start, len_in, cb->compressed_len); + cb->start, len_in, compressed_len); return -EUCLEAN; } diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c index c676e715b4f80..147c92a4dd04c 100644 --- a/fs/btrfs/zlib.c +++ b/fs/btrfs/zlib.c @@ -351,7 +351,7 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb) int wbits = MAX_WBITS; char *data_in; size_t total_out = 0; - size_t srclen = cb->compressed_len; + const size_t srclen = bio_get_size(&cb->bbio.bio); unsigned long buf_start; bio_first_folio(&fi, &cb->bbio.bio, 0); diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c index 3e847b91dae3f..41547ff187f65 100644 --- a/fs/btrfs/zstd.c +++ b/fs/btrfs/zstd.c @@ -587,7 +587,7 @@ int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb) struct btrfs_fs_info *fs_info = cb_to_fs_info(cb); struct workspace *workspace = list_entry(ws, struct workspace, list); struct folio_iter fi; - size_t srclen = cb->compressed_len; + size_t srclen = bio_get_size(&cb->bbio.bio); zstd_dstream *stream; int ret = 0; const u32 blocksize = fs_info->sectorsize;